Hello There.
I can understand your concern.
This couldn't be jet lag.
Is it the first time he is having this issue or he has had it in the past?
as him to drink plenty of fluids, have a soft diet, avoid oily and spicy foods.
i would also suggest you to consult a general surgeon in person for further evaluation and management.
Best regards,
Dr. Anil kumar jain.

Seems like a simple thing as acute Gastroenteritis.
It happens by eating something that is infected or infected water.
Just take tab Oflox-Oz twice daily. Just drink liquids.
Is he also getting fever ?
Is their any other medicine he is taking ?
Whats his current blood pressure?
Temperature?